I saw this on the forums but I don't believe there's an actual ticket for it.

Utilizing rooftops and hard to reach areas can often be a deciding factor on an assault, or during a mission. Having the ability to boost your buddy up onto a rooftop would be really useful, or walk out onto a balcony, and grab the ledge to climb up, perhaps using your buddy for this as well.

Perhaps weight can play a factor into this, as clearly someone carrying 50kg of gear with a rucksack can't simply grab the ledge of a rooftop and haul himself up.